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排序方式: 共有442条查询结果,搜索用时 15 毫秒
91.
Sidra N. Ahmed Mushtaq Ahmad Muhammad Zafar Sofia Rashid Ghulam Yaseen Shazia Sultana Zafar Siddiq Omer Kilic Fethi A. Ozdemir Sadaf Kayani 《Microscopy research and technique》2019,82(7):1174-1183
The medicinal plants are utilized globally considering the cheap and chemical free source, but their correct identification and authentication is prerequisite for safety and efficacy of plant‐based medicines. The present study encompassed traded medicinal plants (16) with high therapeutic value from diverse families like Brassicaceae, Berberidaceae, Malvaceae, Salicaceae, Myrtaceae, Papilionaceae, Ascelpiadaceae, Colchicaceae, Violaceae, and Vitaceae for detailed microscopic study of characters that is, morphology, pollen shape and sizes, P/E ratio, pore length and width, spine length, colpi dimensions, and exine sculpture pattern. The plants showed noteworthy differences in microscopy of Wattakaka volubilis having pollinia, translator and corpusculum like structures while pores were visible in Colchicum luteum, Alcea rosea, and Hibiscus syriacus. The spines were observed in Centipeda minima, A. rosea, and H. syriacus being dimorphic spines in A. rosea and monomorphic in H. syriacus. The exine sculpturing pattern was reticulate in mostly studied plants however distinctive exine pattern was noted in Berberis aristata and Berberis lyceum. The highest polar diameter, equatorial diameter and exine thickness among studied plants were observed in H. syriacus (161 μm), C. luteum (50 μm) and Vitis jacquemontii (1.10), respectively. Thus, microscopy of medicinal plants in addition to other taxonomic evidence offers a supportive skill in authentication, consequently utilization by local consumers and pharmaceutical industries. 相似文献
92.
S Shaheen 《Canadian Metallurgical Quarterly》1997,314(7086):987-988
93.
K Hameed T Gibson M Kadir S Sultana Z Fatima A Syed 《Canadian Metallurgical Quarterly》1995,34(3):252-256
Using previously applied methods a survey of joint symptoms was undertaken among 4232 adults, evenly distributed between affluent and poor areas of Karachi, Pakistan. Only six cases of definite rheumatoid arthritis (RA) (1958 ARA criteria) were identified in the 245 persons who complained of joint problems of at least 4 weeks duration. The prevalence was 0.9 [confidence interval (CI) 0.21-3.61] and 1.98 (CI 0.55-5.1) per thousand in the poor and affluent districts, respectively. These were substantially less than prevalence rates reported in the West but were similar to figures derived from other developing countries. There was no obvious impact of current living standards on the findings. The relative paucity of older female subjects in both the affluent and poor communities may account at least in part for the low rates observed. The infrequency of rheumatoid nodules in Southern Asians with RA illustrates the difficulty of applying existing diagnostic criteria to this community. 相似文献
94.
AA Siddiqui T Sultana NP Buchholz MA Waqar J Talati 《Canadian Metallurgical Quarterly》1998,26(6):383-388
The iron status of a national sample of adults living in France and participating in the SU.VI.MAX cohort, was assessed using serum ferritin and hemoglobin concentrations. Complete data were obtained for 6648 women 35-60 y old and for 3283 men 45-60 y old. Assessment of iron dietary intakes was realized on a subsample of 3111 women and 2337 men who reported six 24 h dietary records during a one-year period; 22.7% of menstruating women and 5.3% of post-menopausal women presented a total depletion of iron stores (serum ferritin < 15 microg/l). Iron-deficient anemias were found in, respectively, 4.4% and less than 1% of these women. Three-quarters of the anemias were related to iron deficiency in menstruating women. In men, iron depletion and iron deficiency anemia were very rare. Post-menopausal women had much higher serum ferritin levels than menstruating women. In menstruating women, those using intrauterine devices had significantly lower serum ferritin levels than those without contraception, and much lower than those using oral contraception. The frequency of iron depletion reached 28.1% in women using intrauterine devices, but only 13.6% in those using oral contraceptives. The mean iron intake was 16.7 +/- 5.7 mg/d in men and 12.3 +/- 3.4 mg/d in women. Heme iron represented respectively, 11.1 and 10.4% of iron intake. Ninety-three percent of menstruating women had dietary iron intakes lower than recommended dietary allowances (RDA); 52.6% consumed less than two thirds of these RDA. In post-menopausal women and men, respectively 27.7% and 3.6% had dietary intakes lower than RDA. Serum ferritin was positively correlated with meat, fish and total iron intake, and negatively correlated with dietary products consumption, calcium and fiber intake. 相似文献
95.
96.
In this paper we address the problem of controlling multiple non redundant robots manipulating a rigid object cooperatively when the parameters of the robots and the parameters of the load are uncertain. We propose a controller that takes into account the dynamics of both the load and the manipulators. The linearity of the dynamics of the robots and the load, with respect to the unknown parameters, is exploited during the derivation of the parameter's adaptation scheme. In order to design control and update laws that do not require the measurements of the joint accelerations or the load acceleration, the dynamics of both the robots and the load are filtered through a stable first order filter. Two prediction error vectors are then defined as the difference between the measured filtered dynamics and the predicted filtered dynamics of both the robots and the load. The least-squares estimation method or gradient method can be used to estimate the parameters of the multi-robot system from the prediction errors. We then develop a controller that is based on the cancellation of the nonlinearities. The proposed controller guarantees asymptotic tracking of the load trajectories and also guarantees asymptotic tracking of the internal forces trajectories. 相似文献
97.
Potassium‐Ion Battery Anode Materials Operating through the Alloying–Dealloying Reaction Mechanism
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Irin Sultana Md Mokhlesur Rahman Ying Chen Alexey M. Glushenkov 《Advanced functional materials》2018,28(5)
Anode materials that operate via the alloying–dealloying reaction mechanism are well known in established and maturing battery systems such as lithium‐ion and sodium‐ion batteries. Recently, a new type of metal‐ion battery that utilizes K+ ions in its operating principle has attracted significant attention due to a possibility of building high voltage cells using an abundant potassium ionic shuttle. Establishing promising electrode materials is of paramount importance for this new type of battery. This feature article summarizes available early results on the alloying–dealloying anode materials in potassium electrochemical cells. Based on original research (some data are presented for the first time) and independently published literature, experimental results on silicon, tin, phosphorus, antimony, and lead‐containing anodes are critically discussed. The electrochemical properties, charge storage mechanisms, and achievable capacities are considered. The results are compared with the behaviors of the same materials in lithium and sodium cells, and the importance of the volumetric parameters of electrodes is emphasized. Finally, a number of further research directions in these interesting anode materials are suggested. The feature article provides a useful reference for the growing number of researchers and specialists working in the field of emerging metal‐ion batteries with non‐lithium chemistries. 相似文献
98.
Abou El-Ela Adel A. El-Sehiemy Ragab A. Shaheen Abdullah M. Diab Abd El-Gelil 《Neural computing & applications》2021,33(14):8459-8477
Neural Computing and Applications - Recently, the renewable energy has been occupied a lot of attention around the world since it presents cheap and sustainable energy. Consequently, its presence... 相似文献
99.
100.
C. N. Bailey J. S. Adams S. R. Bandler J. A. Chervenak M. E. Eckart A. J. Ewin F. M. Finkbeiner R. L. Kelley C. A. Kilbourne F. S. Porter J. E. Sadleir S. J. Smith M. Sultana 《Journal of Low Temperature Physics》2012,167(3-4):236-241
Microcalorimeters onboard future x-ray observatories require an anti-coincidence detector to remove environmental backgrounds. In order to most effectively integrate this anti-coincidence detector with the main microcalorimeter array, both instruments should use similar read-out technology. The detectors used in the Cryogenic Dark Matter Search (CDMS) use a phonon measurement technique that is well suited for an anti-coincidence detector with a microcalorimeter array using SQUID readout. This technique works by using a transition-edge sensor (TES) connected to superconducting collection fins to measure the athermal phonon signal produced when an event occurs in the substrate crystal. Energy from the event propagates through the crystal to the superconducting collection fins, creating quasiparticles, which are then trapped as they enter the TES where they produce a signal. We are currently developing a prototype anti-coincidence detector for future x-ray missions and have recently fabricated test devices with Mo/Au TESs and Al collection fins. We present results from the first tests of these devices which indicate a proof of concept that quasiparticle trapping is occurring in these materials. 相似文献